Various types of heart valve prostheses have been developed which operate hemodynamically as a result of the pumping action of the heart and which are in essence functioning as check valves. Early heart valves employed a ball-and-cage arrangement whereas later versions of heart prostheses have employed one or more occluders generally in the form of a plate or disc which might be flat or of a curved shape. Bokros U.S. Pat. No. 3,546,711 shows a heart valve having a circular occluder which is pivoted from a hinge pin that coacts with a pair of upstanding fins located on the downstream surface of the occluder. Bokros U.S. Pat. No. 4,178,639 shows a bi-leaflet heart valve having a pair of platelike members each of which has ears extending from its opposite lateral edges that pivot in spheroidal guides located in the orifice ring. U.S. Pat. No. 3,445,863 shows a heart valve arrangement having one or more occluders in the form of flat plates having cut-outs at their edges which are proportioned to interfit with complementary cut-outs in a base ring formed of generally similar material. U.S. Pat. No. 4,225,980 shows a metallic heart valve which includes an oval-shaped occluder having cut-outs in opposite lateral edges which coact with parabolic pivots or pegs that extend radially inward from the interior surface of the orifice ring. U.S. Pat. No. 4,078,268 shows a bi-leaflet valve having a pair of semicircular occluders which have ears extending upward from the downstream surface thereof that co-act with fulcrums to effect a pivoting action. U.S. Pat. No. 4,159,543 shows a variety of bi-leaflet valves, one version of which has grooves cut into the edges of the semicircular occluders at an oblique angle to the surface thereof, which grooves receive generally conical pivot pins that extend radially inward from the interior surface of the orifice ring. U.S. Pat. No. 4,373,216 illustrates heart valves having one or more occluders that have notches in opposite edges of the periphery thereof which co-act with elongated protuberances extending inward from the surface of the orifice ring and providing tracks for guiding pivotal and translational movement of the occluders.
As is apparent from the foregoing, a wide variety of different heart valves have been designed, and work continues on new heart valve designs in order to still farther improve the functioning of these prostheses which are being used in greater quantity each year as surgical techniques improve throughout the world.